The art of music is no longer limited to the sounding models of instruments and voices. Electroacoustic music opens access to all sounds, a bewildering sonic array ranging from the real to the surreal and beyond. For listeners the traditional links with physi-cal sound-making are frequently ruptured: electro-acoustic sound-shapes and qualities frequently do not indicate known sources and causes. Gone are the familiar articulations of instruments and vocal utter-ance; gone is the stability of note and interval; gone too is the reference of beat and metre. Composers also have problems: how to cut an aesthetic path and discover a stability in a wide-open sound world, how to develop appropriate sound-making methods, how to select technologies and software. How are we to explain and understand electro-acoustic music? Music is not created from nothing. If a group of listeners ﬁnds a piece of electroacoustic music ‘rewarding’ it is because there is some shared experiential basis both inside and behind that music. We need to be able to discuss musical experiences, to describe the features we hear and explain how they work in the context of the music.